Conveyor system

ABSTRACT

A conveyor system comprising a conveyor for transporting articles from any selected one of a plurality of input devices to any selected one of a plurality of output devices having conveyor position means for indicating movement of said conveyor and logic control means for selecting the input and output devices and synchronizing discharge to and from said conveyor with the movement thereof. The system comprises conveyor position sensor having an opaque sensor wheel driven by a drive wheel of a belt or chain conveyor. The sensor wheel is formed with a plurality of concentric, annular rows of signal means, with the signal means of each row spaced apart a rotational distance corresponding to a predetermined linear distance of the conveyor belt or chain. Photoelectric and magnetic means are provided to sense passing of the signal means as the sensor wheel is rotated and the conveyor belt is moved.

ited States Patent 1 Lee et a1.

[11] 3,738,475 51 June 12, 1973 1 CONVEYOR SYSTEM [75] Inventors:Kirkwood M. Lee, Ogden; Arlyn G.

Liddell, Bountiful, both of Utah [73] Assignee: Eaton Corporation,Cleveland, Ohio [22] Filed: July 16, 1971 [21] Appl. No.: 163,192

OTHER PUBLICATIONS RCA Technical Notes, Tn No. 802, J. Y. Avine, Nov.15, 1968, pp. l-5. Controlling with Photoelectrics, Wilburn, J. E. Nov.

f INPUT CHUTES 1965, Automation, pp. 93-103.

Primary Examiner-Evon C. Blunk Assistant Examiner-Douglas D. WattsAttorneyLynn G. Foster [57] ABSTRACT A conveyor system comprising aconveyor for transporting articles from any selected one of a pluralityof input devices to any selected one of a plurality of output deviceshaving conveyor position means for indi' cating movement of saidconveyor and logic control means for selecting the input and outputdevices and synchronizing discharge to and from said conveyor with themovement thereof. The system comprises conveyor position sensor havingan opaque sensor wheel driven by a drive wheel of a belt or chainconveyor. The

sensor wheel is formed with a plurality of concentric, annular rows ofsignal means, with the signal means of each row spaced apart arotational distance corresponding to a predetermined linear distance ofthe conveyor belt or chain. Photoelectric and magnetic means areprovided to sense passing of the signal means as the sensor wheel isrotated and the conveyor belt is moved.

3 Claims, 4 Drawing Figures CHUTE;

CONTROL m LOGIC UNIT PAIENTEDJUM 2 ma sum 1 or 2 r INPUT CHUTES CHUTEECONTROL LOGIC llll UN IT jl PATENTEB 1 2 SHEET 2 [IF 2 38 3 coDE CODE 5CODE 1 READING READING READING sTATIoN sTATIoN STATION 3a KYBD coDEINTERFACE READING LOGIC STATION 238 CONVEYOR POSITION I SENSORPROGRAMMABLE CONTROLLER I25 22 (COMPUTER) A a. B DIGITIAL \INPUTINTERFACE PULSES OUTPUT BUFFER 40 SOLD BUFFERS 5 STATE RELAY DIscI-IARGEMECHANISM 55R ,40 INPUT DISCHARGE coNvEvoR MECHANISM CONTROL j DISCHARGEMECHANISM ssR To DUMP CONTROL OF CONVEYOR ss R FIG. 3

CONVEYOR SYSTEM BACKGROUND l. Field of Invention This invention relatesto article conveyors and is particularly directed to conveyor systemsand means for sensing the position of an endless belt or chain conveyorand providing electrical signals indicative of such positions which maybe employed for controlling operation of the conveyor or like purposes.

2. Prior Art Endless belt or chain conveyors have long been used fortransporting articles from one position to another within a factory,warehouse, assembly line, or the like. Where liquids or particulatematerials are to be transported by belt or chain conveyors, receptaclesfor such substances are frequently secured to the conveyor belt or chainat spaced intervals therealong. These receptacles are loaded at oneposition of the conveyor, transported with the conveyor belt or chain,and emptied at a second position of the conveyor. Obviously, unless thereceptacles are precisely positioned during the loading and emptyingoperations, spillage may occur which is wasteful and, depending upon thematerial transported, may be dangerous to persons or property in thevicinity. Moreover, this problem is aggravated when attempts are made tocontrol operation of the conveyor by means of a computer or the like orto synchronize the movements of two conveyors, for example, to cause oneconveyor to deposit an article in a particular container carried by asecond conveyor. Unfortunately, no satisfactory technique has beenproposed heretofore for indicating the position of a conveyor or ofarticles carried thereby. Attempts have been made to control conveyorson the basis of the speed of the conveyor and the time required to movebetween given positions. However, such attempts have been woefullyinadequate or extremely expensive. Other prior art systems have employedlimit-type switches which are mechanically closed by engagement with thearticles carried by the conveyor. However, where high speed conveyorsare employed, such systerns are frequently subject to overrunning.Moreover, where computer control is employed, such switch often resultsin arcing, production of transients, and other sources of noise whichtend to interfere with the computer operation.

BRIEF SUMMARY AND OBJECTS OF THE INVENTION These disadvantages of theprior art are overcome with the present invention and a conveyor systemis provided employing a position sensor which coordinates ingress andegress of articles to and from an article conveyor and which accuratelyand reliably indicates the position of articles carried by the conveyor,together with providing indications of incremental distances betweensuch articles, and which is compatible with computer control systems andthe like for synchronizing, depositing and removing of articles withselected conveyor positions.

Advantages are preferably attained by providing a sensor wheel which isrigidly coupled to and driven by one of the conveyor drive wheels. Thesensor wheel is formed with concentric annular rows of signal means; thesignal means of one row being spaced to correspond to the location ofarticles carried by the conveyor, and the signal means of the second rowbeing spaced to correspond to incremental distances between adjacentsuch articles. In one form of the invention, the signal means areapertures formed in the sensor wheel and photoelectric means arepositioned adjacent the sensor wheel to provide electrical signals inresponse to passage of light through the apertures as the conveyor isoperated and the sensor wheel is rotated. In an alternative form of theinvention, the signal means are magnets having focused fields andmagnetic sensing meansare positioned adjacent the sensor wheel toprovide electrical signals in response to passage of the magnets. Ineither case, the resulting signals may, then, be supplied to a controlsystem to precisely monitor the positions of the articles carriedthereby. Moreover, these techniques avoid electromechanized switchingand, hence, eliminate significant sources of noise. It is a primaryobject of this invention to provide an automated conveyor system forcommunicating articles.

It is also a significant object to provide a conveyor system wherein theingress and egress of articles thereto and therefrom is automaticallycontrolled in synchronization with selected positions on the conveyor.

It is also'a meaningful object of the present invention to provideimproved means for indicating the position of belt conveyors andarticles carried thereby.

Another object of the present invention is to provide conveyor positionsensing means which will sense the positon of articles carried by theconveyor, together with incremental distances between such articles.

A further object of the present invention is to provide conveyorposition sensing means which will establish electrical signalsindicative of the position of articles carried by the conveyor andincremental distances between such articles.

An additional object of the present invention is to provide a conveyorposition sensing means which is compatible with computer control systemsand the like.

A specific object of the present invention is to provide conveyorposition sensing means copmprising a sensor wheel rigidly connected toand driven bY one of the drive wheels of a belt or chain conveyor, saidsensor wheel being formed with a plurality of concentric annular rows ofsignal means with the spacing of the signal means in each of said rowscorresponding to a respective distance of travel of said conveyor; andsignal sensing means positioned adjacent said sensor wheel and servingto establish electrical signals in response to passage of said signalmeans as the conveyor is moved and said sensor wheel is rotated.

These and other objects and features of the present invention will beapparent from the following detailed description, taken with referenceto the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic representationshowing a belt conveyor system embodying the position sensor of thepresent invention;

FIG. 2 is a diagrammatic representation showing the signals output bythe position sensor of FIG. 1 as functions of time;

FIG. 3 is a diagrammatic representation of the control system of theconveyor system of FIG. 1; and

FIG. 4 is a transverse section through an alternative form of the sensormechanism of the conveyor system of FIG. 1.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT In that form of thepresent invention chosen for purposes of illustration, FIG. 1 shows abelt conveyor, indicated generally at 2, comprising an endless belt 4which passes about, and is driven by, drive wheels 6 and 8. A pluralityof containers 10 are carried by the conveyor 2 and are located atpredetermined intervals along the belt 4. One of the conveyor drivewheels, for example, wheel 6, is also coupled to drive a sensor wheel12. The sensor wheel 12 is composed of opaque material and is formedwith a plurality of concentric annular rows of apertures, as indicatedat 14 and 16, which extend completely through sensor wheel 12. Theapertures of row 14 are spaced apart a rotational distance correspondingto the predetermined distance between adjacent ones of the containers 10carried by conveyor 2, as indicated at A, while the apertures of row 16are spaced apart a rotational distance corresponding to a predeterminedincrement of the distance between the containers 10, as indicated at B.A light source 18 is positioned adjacent one side of sensor wheel 12,while a pair of photoelectric cells 20 and 22 are located adjacent theopposite side of sensor wheel 12. Photocell 20 is positioned to senselight passing through the apertures of row 14 of sensor wheel 12, andphotocell 22 is positioned to sense light passing through the aperturesof row 16 of sensor wheel 12. The outputs from photocells 20 and 22 aresupplied to the conveyor control system logic 25 for purposes which willbe explained below;

In use, the containers 10 are deposited on the belt 4 of conveyor 2 atpredetermined intervals, which may be controlled by the conveyor controlsystem logic and may be synchronized thereby to coincide with emissionof a pulse from photocell 20. The rate of movement of belt 4 isdetermined by drive wheel 6 which also serves to rotate sensor wheel 12.Since sensor wheel 12 is opaque, it will block passage of light fromsource 18 to the photocells 20 and 22. However, as the sensor wheel 12is rotated, the apertures of rows 14 and 16 will be successivelyinterposed between source 18 and the photocells 20 and 22 and will allowpassage of light to the photocells 20 and 22, causing the photocells 20and 22 to emit a series of electrical pulses. Due to the spacing of theapertures of row 14, photocell 20 will emit a series of pulses as seenby curve A in FIG. 2, each corresponding to the position of a respectiveone of the containers 10 carried by conveyor 2. Similarly, photocell 22will emit a series of pulses, as seen by curve B in FIG. 2, eachcorresponding to a predetermined increment of the distance betweenadjacent ones of the containers'lO. The pulses from the photocells 20and 22 are supplied to the conveyor control system logic 25 to aid incontrol of the conveyor.

A plurality of input units such as conveyors or chutes are provided, asindicated at 24, 26, and 28, respectively, and each carry articles to bedeposited in the containers 10 of conveyor 2. In addition, a pluality ofoutput units such as conveyors or chutes, indicated at 32, 34, and 36,respectively, are provided at a point along conveyor 2 spaced somedistance from the input conveyors 24, 26, and 28. It may be desirable tosend successive ones of the articles 10 from any given one of the inputconveyors 24, 26 or 28 to different ones of the output conveyors 32, 34,and 36.

Thus, or example, in a post office operation, a plurality of mail trucksmight collect mail from mail boxes in respective areas of a city anddeliver the mail in an unsorted or partially sorted condition torespective ingress chutes or conveyors 24, 26, 28. Each of the inputconveyors 24, 26, and 28 has signal input means such as a code readingstation 38 and a discharge mechanism 40. If desired, weigh stations orother appropriate means may also be provided. The code reading stations38 may comprise a human operator with a keyboard or apparatus forautomatically reading the code identification of each article 30awaiting discharge from the ingress conveyor and for communicating thisidentifcation information to the control logic unit 26. Assume, by wayof example, that the first of the articles 30 on input conveyors 24 and28 are to be delivered to New York and, hence, to output conveyor 32,while the first article 30 on input conveyor 26 is to be delivered toLos Angeles and, hence, to output conveyor 36. This information istransmitted to the control logic unit 25, as best seen in FIG. 3, by therespective code reading stations 38. The control logic unit 25 thencompares this information with the data from photocells 22, whichindicate the positions of the containers 10 carried by conveyor 2, andtriggers displacement of the ingress conveyor and actuates the dischargemechanisms 40 thereof (FIG. 1) in synchronization with the location andrate of conveyor displacement of a suitable empty one of the containers10 of conveyor 2, such that the correct container and the article arriveat a common location at the same time. Thus, the logic unit 25 wouldtrigger the dump mechanisms 40 of input conveyors 24 and 26 to cause theNew York-bound articles 30 from input conveyor 24 to be deposited incontainer 42 of conveyor 2 and the Los Angeles-bound article 30 frominput conveyor 26 to be deposited in container 44 of conveyor 2. Thelogic unit 25, then, waits until conveyor 2 has moved container 44 pastinput conveyor 28 and, when container 42 is moved adjacent inputconveyor 28, the logic unit 25 triggers the discharge mechanism 40 ofinput conveyor 28 to cause its New Yorkbound article 30 to be depositedin container 42 along with the New York-bound article 30 from inputconveyor 24. The logic unit 25 continues to track the movement ofcontainers 42 and 44 and, when container 44 is positioned adjacent theLos Angeles output conveyor 36, the logic unit 25 actuates appropriatedump mechanism on container 44 causing the Los Angeles-bound article 30from input conveyor 26 to be deposited on the output conveyor 36.Similarly, when container42 is positioned adjacent the New York outputconveyor 32, the logic unit 25 actuates the dump mechanism of container42 to cause the New Yorkbound articles 30 from input conveyors 24 and 28to be deposited on output conveyor 32. Obviously, numerous types ofdevices may be employed for transferring the articles 30 from the inputconveyors 24, 26, and 28 to conveyor 2 and from conveyor 2 to the outputconveyors 32, 34, and 36. However, the details of such transfer devicesform no part of the present invention. Moreover, although the articles30 have been referred to as mail articles or sacks, by way of example,the system is equally useful with other types of articles. Further,although conveyor 2 has been described as carrying containers 10, it iscontemplated that the articles 30 could be placed directly on theconveyor 2 without the use of containers 10.

FIG. 4 illustrates an alternative form of position sensing mechanism foruse with the conveyor 2. In this form of the invention, a plurality offocused field magnets 46 are provided, each mounted in a respective oneof the apertures of sensor wheel 12 nd the photocells 22 are replaced bya housing 48 containing a pair of magnetic field sensing devices, suchas Magnistors, manufactured by the Hudson Company of Manchester, NewHampshire. Thus, as the sensor wheel 12 is rotated, the magnets 46 arecaused to move past the magnistors 50 and produce a changing magneticflux, which is converted into an electrical signal by the magnistors 50and is passed to the control logic unit 25.

Obviously, numerous variations and modifications may be made withoutdeparting from the present invention. Accordingly, it should be clearlyunderstood that the form of the present invention described above andshown in the accompanying drawing is illustrative only and is notintended to limit the scope of the present invention.

What is claimed is:

1. A conveyor system comprising:

a plurality of article input chutes;

a plurality of article output chutes;

a conveyor comprising a plurality of article holding containers, eachcontainer capable of holding a plurality of articles and adapted toreceive selected articles discharged from one or more of said articleinput chutes, each operable to discharge all of said articles therein toany selected one of said article output chutes, and drive means fordriving said conveyor;

a sensor wheel connected to be rotated by said conveyor;

a plurality of signal means carried by said sensor wheel the signalmeans being spaced one from another a rotational distance about saidsensor wheel corresponding to a predetermined linear distance 7 alongsaid conveyor;

signal sensing means positioned to sense passage of said signal meansand establishing an electrical sig nal in response to such passage;

a plurality of signal input means, each located adjacent a respectiveone of said article input chutes, each for providing signals identifyingthe desired one of said article output chutes to which an articlecarried by the associated one of said article input chutes is to bedelivered; and

control logic means connected to receive said electrical signals fromsaid sensing means in said signal input means for selectively andsynchronously controlling discharge of articles from said article inputchutes to selected ones of said containers and from said containers tosaid article output chutes.

2. A conveyor system as defined in claim 1 wherein:

said signal input said comprises means for reading an identificationcode carried by sAid articles.

3. The device of claim 1 wherein;

said signal means are disposed in a plurality of concentric annularrows, with the signal means of one of said rows being spaced arotational distance about said sensor wheel corresponding to the lineardistance along said conveyor between adjacent ones of said containersand the signal means of a second of said rows being spaced a rotationaldistance about said sensor wheel corresponding to a predeterminedincrement of the linear distance along said conveyor between adjacentones of said containers.

1. A conveyor system comprising: a plurality of article input chutes; aplurality of article output chutes; a conveyor comprising a plurality ofarticle holding containers, each container capable of holding aplurality of articles and adapted to receive selected articlesdischarged from one or more of said article input chutes, each operableto discharge all of said articles therein to any selected one of saidarticle output chutes, and drive means for driving said conveyor; asensor wheel connected to be rotated by said conveyor; a plurality ofsignal means carried by said sensor wheel the signal means being spacedone from another a rotational distance about said sensor wheelcorresponding to a predetermined linear distance along said conveyor;signal sensing means positioned to sense passage of said signal meansand establishing an electrical signal in response to such passage; aplurality of signal input means, each located adjacent a respective oneof said article input chutes, each for providing signals identifying thedesired one of said article output chutes to which an article carried bythe associated one of said article input chutes is to be delivered; andcontrol logic means connected to receive said electrical signals fromsaid sensing means in said signal input means for selectiVely andsynchronously controlling discharge of articles from said article inputchutes to selected ones of said containers and from said containers tosaid article output chutes.
 2. A conveyor system as defined in claim 1wherein: said signal input said comprises means for reading anidentification code carried by sAid articles.
 3. The device of claim 1wherein; said signal means are disposed in a plurality of concentricannular rows, with the signal means of one of said rows being spaced arotational distance about said sensor wheel corresponding to the lineardistance along said conveyor between adjacent ones of said containersand the signal means of a second of said rows being spaced a rotationaldistance about said sensor wheel corresponding to a predeterminedincrement of the linear distance along said conveyor between adjacentones of said containers.